I like Crayola's - though it can be a bit pricy as far as tempera goes. I used to work for an art company & got to play with lots.
I also love Sargent's powdered tempera - you mix as much as you need, and you can use it for lots of other things, too (coloring plaster, paper mache, etc.)
If it smells funky, you need to contact the mfr. All paints have a shelf life - some shorter than others. It may be contaminated or gone bad.
Here'sa good website I use for my kids supplies, they're local to me, but they ship all over & are pretty cheap. They have all kinds of art supples.
Their Handy Art brand is good and cheap, but you can't find it in stores.
www.unitednow.com